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Re: Question of reason for rule "return value void for event handling delegates"

kstls30-Jun-09 23:49

kstls

30-Jun-09 23:49

http://msdn.microsoft.com/en-us/library/4b612y2s.aspx[^]

An event is an association between a delegate and a member function (event handler) that responds to the triggering of the event and allows clients from any class to register methods that comply with the signature and return type of the underlying delegate.

The delegate can have one or more associated methods that will be called when your code indicates that the event has occurred. An event in one program can be made available to other programs that target the .NET Framework common language runtime

So in short, the delegate is a multicast delegate, and can have more than one method attached and this is basicly the reason that it must be void.

Hope it makes sence Smile | :)

Re: Question of reason for rule "return value void for event handling delegates"

Luc Pattyn30-Jun-09 23:59

Luc Pattyn

30-Jun-09 23:59

when more than one delegate is added to an event, they all get fired; which return value would you hope to get?

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

DISCLAIMER: this message may have been modified by others; it may no longer reflect what I intended, and may contain bad advice; use at your own risk and with extreme care.

Re: Question of reason for rule "return value void for event handling delegates"

Chamundi1-Jul-09 0:08

Chamundi

1-Jul-09 0:08

Thx for the quick answer...considering the multicast issue of delegates/events and the reusability of assemblies it makes sense using a void return value...

Re: Question of reason for rule "return value void for event handling delegates"

Luc Pattyn1-Jul-09 0:30

Luc Pattyn

1-Jul-09 0:30

you're welcome.
BTW: void is not a value, it is a type (or absence thereof, some would say).

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

DISCLAIMER: this message may have been modified by others; it may no longer reflect what I intended, and may contain bad advice; use at your own risk and with extreme care.

Re: Question of reason for rule "return value void for event handling delegates"

Chamundi1-Jul-09 5:09

Chamundi

1-Jul-09 5:09

Oh...yepp...I know...sorry for my unclear expression...I´m no native English speaker...

SmartNavigation

minniemooo30-Jun-09 22:59

minniemooo

30-Jun-09 22:59

Please help.
I have Page.SmartNavigation = true; in my page load but it does not work' My browser does not maintain its last position after the page refreshes.

Re: SmartNavigation

dan!sh 30-Jun-09 23:04

dan!sh

30-Jun-09 23:04

This would fit better in the ASP.Net forum.

Anyways, the first Google search result[^] tells everything about this.

AForge.net writer.Open problem

tvbarnard30-Jun-09 22:47

tvbarnard

30-Jun-09 22:47

Good day

I want to save a video stream to file from my webcam. I looked at Andrew Kirillov's example on "motion detection algorithms" and used the exact same code to test the saving of a video file, but it seams that the writer.Open() method is unable to execute properly.

In my own code (using the "saving video" snippet) I'm given an exception, and when running Andrew's complete source code on the motion detector the program freezes as soon as I start recording.

I am running Vista, so I don't know whether that might be the cause?

This is my code I'm currently using:

SaveFileDialog sfd = new SaveFileDialog( );
			if ( sfd.ShowDialog( ) == DialogResult.OK )
			{
				AVIWriter writer = new AVIWriter( "wmv3" );
				try
				{
					writer.Open( sfd.FileName, 320, 240 ); //where the exception is thrown
					Bitmap bmp = new Bitmap( 320, 240, PixelFormat.Format24bppRgb );
					for ( int i = 0; i < 100; i++ )
					{
						bmp.SetPixel( i, i, Color.FromArgb( i, 0, 255 - i ) );
						writer.AddFrame( bmp );
					}
					bmp.Dispose( );
				}
				catch ( ApplicationException ex )
				{
					lblFps.Text = "Exception thrown";
				}
				writer.Dispose( );
			}

Re: AForge.net writer.Open problem

Eddy Vluggen30-Jun-09 23:18

Eddy Vluggen

30-Jun-09 23:18

What kind of exception / what text is in the error?

I are troll Smile | :)

how to change the File summary information

Joe Rozario30-Jun-09 22:36

Joe Rozario

30-Jun-09 22:36

Dear friends,

please tell me how to change the File summary information ??

My Problem is i have

"own file type"

and i want to change the file summary through c# can u please tell me how to do that?

i mean the file->properties-summary tab information.

please give me any idea? link? or source.

Thank you.

Joe.I

Re: how to change the File summary information

dan!sh 30-Jun-09 23:01

dan!sh

30-Jun-09 23:01

Might help[^].

Re: how to change the File summary information

Joe Rozario1-Jul-09 1:35

Joe Rozario

1-Jul-09 1:35

Dear friend

thanks for your replay.

i have asked the question already ??

With Love

joe.I

"Cannot access a disposed object.\r\nObject name: 'Transaction'."

devvvy30-Jun-09 22:04

devvvy

30-Jun-09 22:04

hello

I ran into this error message while before/while/after insert into ShopMessage...

<br />
   		Message	"Cannot access a disposed object.\r\nObject name: 'Transaction'."	string<br />

I'm using TransactionScope with timeout set to zero (i.e. infinite). Googled a bit still quite clueless.

This is how I wrap Database calls in TransactionScope

<br />
<br />
					using (oScope = new TransactionScope(TransactionScopeOption.Required, TimeSpan.FromMilliseconds(0)))<br />
					{<br />
                                                // Here we have some ADO.NET calls + some NHibernate calls.<br />
						nGeneratedId = SaveCoreOperations(ref oShop);<br />
						oScope.Complete();<br />
					}<br />

Here's the stack trace

<br />
   at System.Transactions.Transaction.get_IsolationLevel()<br />
   at System.Data.SqlClient.SqlDelegatedTransaction..ctor(SqlInternalConnection connection, Transaction tx)<br />
   at System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction tx)<br />
   at System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction tx)<br />
   at System.Data.SqlClient.SqlInternalConnectionTds.Activate(Transaction transaction)<br />
   at System.Data.ProviderBase.DbConnectionInternal.ActivateConnection(Transaction transaction)<br />
   at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)<br />
   at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)<br />
   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)<br />
   at System.Data.SqlClient.SqlConnection.Open()<br />
   at NHibernate.Connection.DriverConnectionProvider.GetConnection()<br />
   at NHibernate.Impl.SessionFactoryImpl.OpenConnection()<br />

Any idea?

dev

Re: "Cannot access a disposed object.\r\nObject name: 'Transaction'."

Manas Bhardwaj30-Jun-09 22:13

Manas Bhardwaj

30-Jun-09 22:13

devvvy wrote:
SaveCoreOperations(ref oShop);

I don't think you need a ref here.

Manas Bhardwaj
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.

Re: "Cannot access a disposed object.\r\nObject name: 'Transaction'."

devvvy1-Jul-09 1:14

devvvy

1-Jul-09 1:14

yes you're right about not needing the ref, but that's not what i am asking either.

I am suspecting TransactionScope called Transaction.Dispose somehow.

dev

Re: "Cannot access a disposed object.\r\nObject name: 'Transaction'."

Manas Bhardwaj1-Jul-09 1:41

Manas Bhardwaj

1-Jul-09 1:41

devvvy wrote:
using (oScope = new TransactionScope(TransactionScopeOption.Required, TimeSpan.FromMilliseconds(0)))
{
// Here we have some ADO.NET calls + some NHibernate calls.
nGeneratedId = SaveCoreOperations(ref oShop);
oScope.Complete();
}

Where is oScope used? Confused | :confused:

Manas Bhardwaj
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.

Re: "Cannot access a disposed object.\r\nObject name: 'Transaction'."

devvvy1-Jul-09 1:41

devvvy

1-Jul-09 1:41

some inside SaveCoreOperation and hint, death came after many iterations

dev

Re: "Cannot access a disposed object.\r\nObject name: 'Transaction'."

Manas Bhardwaj1-Jul-09 1:46

Manas Bhardwaj

1-Jul-09 1:46

But you never passed oScope to this method. It takes the only parameter which is oShop Confused | :confused:

Manas Bhardwaj
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.

Re: "Cannot access a disposed object.\r\nObject name: 'Transaction'."

devvvy1-Jul-09 1:49

devvvy

1-Jul-09 1:49

why'd you need to, scope wraps code whether inline or not between "using" open and close bracket.

using (oScope = new TransactionScope(TransactionScopeOption.Required, TimeSpan.FromMilliseconds(0)))<br />
{<br />
nGeneratedId = SaveCoreOperations(oShop); // This method do direct ADO.NET + NHibernate calls using same connection (I don't think Any open/close/reopen happened here but it's a lot of code in here...)<br />
oScope.Complete();<br />
}

I am suspecting perhaps from within "SaveCoreOperations" oConn used was opened/closed then "Re-opened"... not sure

dev

Re: "Cannot access a disposed object.\r\nObject name: 'Transaction'." [modified]

RussVB25-Aug-09 16:38

RussVB

25-Aug-09 16:38

You can get this error message if your Distributed Transaction Coordinator service is not running. Use Administrative Tools to check the Status of the service has Started and that the Startup Type is Automatic.

Also, the default timeout/timespan is 1 minute and the default machine config caps it to 10 minutes.

modified on Wednesday, August 26, 2009 11:14 PM

Cancel Events

satsumatable30-Jun-09 21:56

satsumatable

30-Jun-09 21:56

Hi
Im placing some controls dynamically on tool strip control and i'm handling that controls click event as well tool strips click event. But when ever i click the control it triggers both the event.

I want to cancel tool strips event when i click the control.. how can i do this?

Re: Cancel Events

DaveyM6930-Jun-09 22:06

DaveyM69

30-Jun-09 22:06

Do you need the toolstrip's Click event to be handled at all (I've never found a need for it personally as all I'm ever interested in is the items, not the strip)?

Dave
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